Odd driveline angles (pic)

[RogueEngineer]

93' FZJ80 with a OME medium springs, armor, rack, ARB bumper, and tire carrier (for reference) and the 2.5" caster correction plates.

I've been dealing with some front end vibration (65+ front end growling/slight vibration through car)and have removed the front driveshaft to try and track it down. Of course, the vibes disappear and I've also noticed some stiff points in the U-joints.

I took some measurements of the driveline angles (see below), and it seems a fair amount off (~3.4 deg). Specifically, the transfer case appears to be tilted upward (front output flange pointing towards hood). Am I right to assume that the transfer case outputs should be parallel to the ground? Could this be due to worn out engine/transmission mounts?

Any input welcome! Bonus pic of the 80 in the middle of the Bonneville Salt Flats!!

Driveline Angles

• RogueEngineer
• Dec 23, 2018

Salt Flats 1 - 2018

• RogueEngineer
• Dec 23, 2018

 

[shocktower]

No they'er not parallel, to the ground, they where, made to be pretty close, to the opposite flanges. Getting them correct can be tough, because, the ground you measure them on can change them a bit, if you have them within + - *4 it should be fine, but you said the Uni's felt notchy you should grease or rebuild them ( only use Japanese Matsuba or OEM ) then try see if it still vibrates

 

[Howard705]

Been having a vibration sometimes worse than others in my neglected stocker. finally pulled the shafts ( no play felt when installled and out of park) and felt the Ujoints. Could feel the notchiness in one of the front shaft joints. Put shaft on from one of my other 80s and smooth as silk at all speeds. (checked wheel brgs, pinions, brake drag, etc,
etc too)

 

[landtank]

what is your measurement between the hub's center and the underside of the fender flare?

 

[mudgudgeon]

Not sure your sketch makes sense?

If u joints are notch or stiff, time for new ones. OEM or Matsuba for longevity

The front diff pinion flange is not parallel to the transfer pinion flange from factory.
Front diff pinion points up by several degrees.

 

[RogueEngineer]

Not sure your sketch makes sense?

If u joints are notch or stiff, time for new ones. OEM or Matsuba for longevity

The front diff pinion flange is not parallel to the transfer pinion flange from factory.
Front diff pinion points up by several degrees.

The sketch shows the flange angles, flange to driveshaft angles, and the drive shaft angle. The top left angle (front diff) is 1.7 deg. left of vertical (\) and the top right angle is the the transfer case @ 3.4 deg right of vertical (/). The two angles at the extreme left and right show the flange-to-driveshaft angles at each end.

That being said - you've actually answered my question. It appears that the angles I'm seeing aren't abnormal despite what the conventional wisdom regarding U-joints states.

Thanks!

 

[RogueEngineer]

what is your measurement between the hub's center and the underside of the fender flare?

Appears to be about 20.5-20.75"

 

[mudgudgeon]

It appears that the angles I'm seeing aren't abnormal despite what the conventional wisdom regarding U-joints states.

For some reason, Toyota ignored conventional wisdom with this, and also installed the front shaft with uni joints out of phase to counter the difference in pinion angle.

 

[landtank]

Appears to be about 20.5-20.75"

Thought it might, pull the plates off. You are basically at stock height and don't need any caster correction.